The present invention relates to an improvement in a railing for a boat conveyor system in a production line.
In a mass production fabrication line where parts are transported and indexed for a series of fabrication steps, it is typically highly desirable to reduce or eliminate downtime in the production line. Because many production lines run all the time (i.e., 24 hours per day and 7 days per week) to keep up with production demands and to maximize the use of each machine, even small amounts of repeated downtime can add up to large expenses due to less efficiency. There can be many different causes of downtime, and thus there is often a continual search for anything that may cause down time so that a solution may be found to reduce or eliminate such downtime. Hence, ways to reduce downtime in a production line are highly desirable.
Another economic consideration for production lines is the life of a part or machine. In general, the more life that can be obtained from a given machine can translate into lower capital expenses, leaving room for higher profit margins. Thus, there is often a continual need or search for ways to make parts and equipment last longer, especially in a mass production line.
In the production of semiconductor devices or electronic devices for example, a part or system being fabricated is often transported from one station to another on a xe2x80x9cboat.xe2x80x9d A xe2x80x9cboatxe2x80x9d in this context is a carriage tray designed to hold a wafer, part, component, or system being produced, and designed to fit within and to be moved by an indexing conveyor system. Sometimes a boat is designed to hold a component firmly and/or in a precise position, whereas some boats merely provide one or more slots or indentations for loosely carrying a component to a subsequent station. FIG. 1 shows an example of a boat 20 used in packaging processes during the production of semiconductor devices. The boat 20 shown in FIG. 1 has an array of cavities 22 formed therein adapted to hold semiconductor chips during packaging processes. During production, indexing the boat 20 with a conveyor system is often used to align the component or system for the next step of fabrication. Hence, if or when the indexing for a station or stations gets out of alignment or gets shifted, it can cause indexing downtime for corrections. Thus, there is a need for a way to decrease indexing downtime in a production line.
One problem that may be a cause of premature part wear and/or indexing errors is friction in the boat conveyer system. Therefore, there is often a need to identify or locate such friction areas and to eliminate or reduce such friction problems.
The problems and needs outlined above are addressed by the present invention. In accordance with one aspect of the present invention, a conveyor system is provided, which comprises: a boat, a railing, and a bearing. The railing is adapted to retain the boat and to define at least part of a path for the boat as it moves along the conveyor system. The bearing is coupled to the railing at a location so that the boat will contact the bearing rather than the railing for at least part of the path as the boat moves along the conveyor system.
In accordance with another aspect of the present invention, a conveyor system is provided, which comprises: a boat, a feed belt, a feed pulley, and railings. The boat is adapted to carry a component therein. The feed belt is driven by the feed pulley. The feed belt is adapted to move the boat along the conveyor system. The railings are adapted to retain the boat and to define a path for the boat. A set of bearings are coupled to each of the railings in locations such that the boat will contact the bearings rather than the railings for at least part of the path as the boat moves along the conveyor system.
In accordance with yet another aspect of the present invention, an improved railing for a conveyor system is provided. The improved railing comprises a set of bearings coupled to the railing and extending from the railing. The bearings are adapted to provide rolling surfaces for a boat that is restrained by the railing as the boat moves along the conveyor system.
In accordance with still another aspect of the present invention, a method of producing an electronic component is provided. The method comprises the steps of: (i) providing a conveyor system comprising: (a) a boat adapted to carry the electronic component therein, (b) a feed belt driven by a feed pulley, the feed belt being adapted to move the boat along the conveyor system, (c) a railing to retain the boat and to define a path for the boat, and (d) a set of bearings coupled to the railing in locations such that the boat will contact the bearings rather than railing for at least part of the path as the boat moves along the conveyor system; (ii) moving the boat from one location to another location with the feed belt; and (iii) directing the path of the boat with the bearings.
In accordance with another aspect of the present invention, a method of improving a conveyor system that is adapted to move a boat along a path defined by one or more railings using a feed belt is provided. The method comprises the step of replacing at least some of the one or more railings with one or more improved railings, wherein the one or more improved railings each comprises a set of bearings coupled to and extending from the improved railing in locations such that the boat will contact the bearings rather than the railing along at least part of the path defined by the one or more railings as the boat moves along the conveyor system. The method may further comprise the steps of: reducing friction between the boat and the one or more railings as the boat moves along the conveyor system as a result of the replacing at least some of the one or more railings step; and reducing wear between the boat and the one or more railings due to the reducing friction step. The method may further comprise the steps of: reducing indexing errors during the step of moving the boat from one location to another location, as a result of the replacing at least some of the one or more railings step; and reducing indexing downtime during production as a result of the reducing indexing error step.